Thread-lock.



W. R. BLAIR. THREAD LOCK.

APPLIOATION FILED JUNE 19, 1011.

1,048,441 l Patented Dec. 24, 1912.

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WILLIAM R. BLAIR, OF ST. LOUIS, MISSOURI, ASSIGNOR TO LANIJIS MACHINE COMPANY, A. CORPORATION OF MISSOURI.

THREAD-LOCK.

Specification of Letters Patent. Patented Dec. 24, 1912.

Application filed June 19, 1911. Serial No. 634,077.

segmental gear and cam 15 having teeth 16 To all 'whom t may concern.'

which inter-mesh with the teeth on the gear Be it known that I, VILLIAH. It. BLAIR, a

citizen of the United States, residing at St. 13. The member 15 is connected by means of Louis, Missouri, have invented a certain new a link 19 to a pivot stud 20 on the thread lever 7. Connected with this same stud 20 is an operating link 21 operatively connected to the main lever 24: of the machine in a. well known manner. The thread leads over the roll S and under the roll 12 through an eye 22 on the bracket 1 between the jaws 4t and 5 of the thread clamp through the arm 9 and over the guide roll 23 fastened on the bracket 1, through the arm 10 to the wax pot.

rIhe above parts are fully described in my aforesaid Patent No. 97 8,832.

My present improvement comprises a link 25 having a slot in its lower end which passes over a bolt 26 adjustably mounted in the slot of the main lever 211 so as to regulate the throw thereof. The upper end of this link is slotted as shown in Fig. 1, said slot co'iperating with the stud 111 so as to be guided thereby, the upper end of the slot lying immediately under the extension 4 of the upper clamping jaw. This upper clampand useful Improvement in Thread-Locks, of which the following' is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part Figure 1 is a detail view of my improved thread lock showing the same open; Fig. 2 is a .similar view showing the parts in edge elevation; Fig. 3 is a view similar to Fig. l, showing the thread lock closed, and Fig. l is a side elevational view of the thread lock and associate parts.

This invention relates to new and useful improvements in thread locks for sewing machines, being designed particularly as an improvement upon the structure shown and described in United States Letters Patent- No. 978,832, granted to me on December 20, 1910.

In the aforesaid invention the thread locking member was operated by a cam whic ing jaw is held against the lower clamping wiped under the movable jaw of the thread jaw 5, the latter being fixed, by means of a lock and consequent-ly was subject to conspring 4t" tcnsioned by a screw 11C. IVhen the siderable wear. main lever 24 rises, it will pass through a My present improvement consists in operc z-nsidcrable are of its movement before the adjustable bolt 26 engages the upper wall of the slot in the end of the link 25. When such engagement occurs, however, the upper spring pressed clamping jaw 4 will be raised so as to release the thread. When the lever descends the spring-pressed jaw I will close on the thread to lock the same, the thread remaining locked during the balance of the excursion of the main lever 211 until said main lever, nearing the end of its upper stroke, again lifts the said clamping jaw.

I claim:

1. In a take-up mechanism including a main lever and thread handling levers, a thread lock, and a link connected to said main lever, and independent of said lock and thread handling levers, for operating said lock.

2, In a take-up mechanism a main lever,

ating the movable jaw of the thread lock by the end thrust of a link having a lost motion connection with the main lever of the machine.

In the accompanying drawings 1 indicates a bracket to be mounted on the overhanging arm of the ordinary wax thread type of sewing machine. On this bracket is a recessed boss within which is mounted the thread clamping device 3 consisting of two jaws 4t and 5, which are operated to clamp the thread therebetween. On a stud 6 is pivotally mounted the thread lever 7 having a thread engaging roll S at one end and thread engaging arms 9 and 10 at the other. Iivoted on this same stud 6 is the take-up lever 11 with thread roll 12 at one end, and a segmental gear 13 at the opposite end. On an adjacent stud 14 is mounted a combined thread handling levers, a thread lock includsignature in the presence of tWo vvitnesses, ing a clamping jaw, and a link mounted on this 16th day of June7 1911.

said main lever and operatinof independently of said thread levers and szid thread look WILLIAM R' BLAIR' and coperating With said clamping jaw to Vitnesses: operate the same; M. P. SMITH. In testimony whereof I hereunto aix my B. S. REID.

v E Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

. Washington, D. G. 

